Fluid pressure control system



March 15, 1949. w, A, EATQN 2,464,636

FLUID PRES-SURE CONTROL SYSTEM Filed July 28, 1945 2 Sheets-Sheet l INVEN TOR.

EaOn/ March 15, 1949. w. A. EATN 2,464,636

FLUID PREsUgE CONTROL SYSTEM SUPPLY JNVENTOR. n/ilfred lBY mfg-fw@HTrORNEK Patented Mar. 15,*l 1949 FLUID PRESSURE CONTROL SYSTEM WilfredA. Eaton, Elyria, Ohio, assignor to Bendix-Westinghouse Automotive AirBrake Company, Elyria, hio, a corporation of Delaware Application July28, 1943,- S'eral"'No.`496,`512

3 Claims.

This invention relates to fluid pressure control mechanism, and moreparticularly to mechanism for controlling the speed of prime movers inairplanes.4

It has previously been proposed to provide fluid pressure operated meansfor controlling the throttle valves of a plurality of engines in orderto synchronize the speeds of the engines, but many of the abovemechanisms' have been unnecessarily complicated as Well as poorlyadapted to remote control operation, and it is accordingly one of theobjects of the present invention to provide mechanism so constructed asto overcome these dii-liculties.

It hase also been common practice in the past, in `connection withairplanes equipped with a plurality of engines for driving the airplane,to provide separate control levers for the throttle valves oi thevarious engines, so arranged as to permit selective or concurrentoperation of the various control levers in order to permitsynchronization of the engine speeds as well as individual control ofthe speeds of the various engines in order to permit steering of theairplane when maneuvering on the ground, and it is an object of thepresent invention to provide a control system soV constituted as topermit the pilot to control the speeds of the engines either selectivelyor concurrently by means of a single control element.

A further object of the invention is to provide means under the controlof a single control element for automatically synchronizing the speedsof the engines, and for permitting the speeds of any separate group ofengines to be individually controlled bythe operation of the singlecontrol element.

Another object of the invention is to provide, in connection with asystem of the above type, Va novel'control valve mechanism actuated byvasingle control element for either selectively or concurrentlycontrolling the speeds of a plurality of engines.

Yet another object of the invention is to provide, in a system of theabove type, means for automatically controlling the throttle valves ofthe engines to maintain the speeds of the engines in synchronismregardless of changes in the relative operating eiciencies of theengines.

A still further` object of the invention is t0 provide, in a system ofthe above type, simple and efficient lmeans for indicating to thev pilotany change inthe relative eiiicience's of the variousy engines. Y

These' and other-objects and novel features of the invention will bemore readily apparent when taken in connection with the accompanyingdrawings, wherein one form of the invention is illustrated. It is to beexpressly understood, however, that -the drawings are employed for thepurpose of illustration only, and are not designed as a definition ofthe limits of the invention, reference beingv had for this purpose tothe appended claims. I Y

In the drawings:

Fig. 1 is a diagrammatic representation, partially -in section, of afluid pressure control system constructedin accordance with theprinciples of the present invention; 1 f Fig. 2 is a view, partially insection, of one of the control valves;

Fig. 3 is a view showing a side elevation of the valve illustrated inFig. 2, and

Fig. 4 is a fragmentary view of the cam and lever utilized in theconstruction of the above valve.

'Referring more particularly to Fig. l of the drawings, the invention isillustrated as applied to an airplane, not shown, provided with engines6 and 1, these engines being provided respectively With intake manifolds8 and 9 and Carburetors I0 and -I I, these carburetors being providedwith the conventional throttle valves, not shown, adaptedrespectively tobe operated through the medium of throttle valve shafts I2 and I34 andlevers-I4 and I5 operatively connected thereto; Fluid actuators I6 andI1 are provided for operating the above levers, these actuators beingprovided with pistons I8 and I9 connected with levers I4 and I5 throughthe medium of connecting rods 20 and 2l, as shown, the pistons andconnecting rods normally being maintained in the positions shown bymeans of the customary return springs 22 and 23. A fluid pressurereservoir 24 is provided, and supplied With uid pressure from a suitablecompressor, not shown, through a conduit 25, the reservoir beingconnected with the actuator I6 through a conduit 26, a conduit 21 and aconduit 28, and with the actuator I1 through conduit 26 and a conduit29. Communication between conduits 21 and 28 is controlled by means of acentrifugal valve mechanism 30, communication between `conduits 26and129 being controlled by an identical centrifugal valve mechanism 3I.The -centrifugal valve mechanisms 30 and 3| are provided with drivingpulleys 32 and 33, respectively driven by the engines 6 and '1 throughthe medium of suitable belts 34 and 35 as shown, this-action servingtocontrol the operation of the valve mechanisms as will be more fullydescribed hereinafter. In addition to the foregoing, means are alsoprovided for controlling the operation of valves 36 and 3l by theapplication of fluid pressure from the reservoir 24, this application offluid pressure being controlled by means of an operators control valvemechanism 36, the valve mechanism being supplied with fluid pressurefrom the reservoir through conduit 26 and a conduit 3l, and serving tosupply fluid pressure to the valves 36 and 3l through conduits 38 and 39respectively. Pressure gauges 46 and 4| are also provided adjacent theoperators position. The gauge 46 is connected with the Vactuator I6through a conduit 42 and conduit 28, while the gauge 4| is connectedwith actuator I1 through a conduit 43 and conduit 29, the gauges thusserving to advise the operator of the pressure supplied to the actuatorsfor reasons which will be more fully described hereinafter.

In view of the fact that the control valves 30 and 3l are identical inconstruction, it will be understood that a description of the valve 30,shown in section in the drawing, will also serve to describe theoperation ofthe valve 3|. The valve 36 is provided with a casing 44provided with an inlet chamber 45, an outlet chamber 46, an exhaustchamber 4l` provided with an atmospheric outlet 48, and a controlchamber 49. A ported partition 50 serves to separate the chambers 45 and46, communication between the chambers being normally prevented by meansof an inlet valve l provided with a stem 52 having an exhaust valve 53mounted in the left end thereof, the inlet valve being normallylmaintained in the position shown by means of a spring 55 interposedbetween the exhaust valve and the left face of the partition. Thechambers 41 and 49 are separated by means of a ilexible diaphragm 55,the diaphragm being connected at its center to a' valve operatingelement 56 slidably mounted in a bore 57 formed in the chamber 46, aflexible sealing ring 58 serving 'to guide the valve operating elementand at the same time to prevent the passage of fluid from chamber 46 tochamber 4l between the wall of the bore 51 and the outer wall of thevalve operating element 56. A centrally located bore 59 is provided inthe element in line with the exhaust valve 53, the right end of the borebeing adapted to close on contact with the exhaust valve, and the leftend of the bore being connected with the exhaust chamber l1 through themedium of a port 66 formed in the wall of the bore. The diaphragm andvalve operating element are ordinarily biased to the left by means of aspring 6l interposed between the right face of the diaphragm and thecasing. Thus it will be understood that with the parts in the positionshown, the inlet valve serves to prevent communication between theconduits 2l and 26 and to permit communication between conduits 28 and48, movement of the valve operating element to the right serving tofirst close the exhaust valve and prevent communication between conduits28 and 48, and serving on further movement to the right to open theinlet valve and permit communication between conduits 21 and 28. Asshown in the drawing, the chamber 49 is adapted to be supplied withfluid pressure from the reservoir 24 through the medium of conduits `26and 31, control valve 36 and conduit 38, and it will therefore beunderstood that on operation of the control valve 36 to supply fluidpressure to the chamber 49, the diaphragm and the valve operatingelement will be moved to the right to close the exhaust valve and openthe inlet valve to supply fluid pressure to the actuator i6 as abovedescribed. As the pressure builds up in the outlet chamber 46, thispressure will act on the are-a of the valve operating element 56 tooppose the force exerted by the diaphragm, it being noted that the valvemechanism can be so constructed as to provide any desired relationbetween the area of the diaphragm and the area of the valve operatingelement 56. The throttle actuator I6 is normally so positioned as tomaintain the throttle valve of the carburetor i0 in idling position, andwith the engine stationary or running at idling speed the valve partsalready described occupy the positions shown.

In order that the valve operating element 56 may be controlled by thespeed of the engine, the pulley 32 is connected with a shaft 62 r0-tatably mounted in the casing 44 and provided at its right end with aspider 63 provided with a plurality of lugs similar to lug 64 for thepurpose of mounting suitable centrifugal weights. One of the weights 65is illustrated as mounted pivotally on the lug 64 by means of a suitablepivot pin 65, the weight further being provided with a lever 6l havingits upper end in engagement with a groove 58 formed in a collar 69slidably mounted for endwise movement with respect to the spider, andmounted for rotation therewith by means of a pin 'I6 carried by thespider and having its lower end in engagement with a keyway 'll formedon the outer surface of the collar 69. The left side of the diaphragm isprovided with a plunger "l2 affixed thereto in line with the valveoperating element 56 and slidably mounted in the casing, the left end ofthe plunger being in operative engagement with the collar 69 through themedium of a ball bearing 12a of conventional type having its inner racemounted for movement with the plunger as shown and the outer racemounted for ymovement with the collar. Thus, on application of fluidpressure to the chamber 49 to move the diaphragm to the right, withcorresponding closing of the exhaust valve and opening of the inletvalve to connect conduits 21 and 28 and supply fluid pressure to theactuator I6 to open the throttle valve and increase the speed of theengine, it will be seen that the speed of the shaft 62 and the attachedspider 53 will also increase correspondingly, with the result that theweight 65 and the other weights on the spider, which are connected inlike manner with the collar 59, will be forced outward under the actionof centrifugal force to cause counter-clockwise rotation of the weightsand the application of a force tending to move the collar 69 to theleft. This force will tend to oppose and balance the force exerted tothe right by the action of fluid pressure on the diaphragm 55, and itwill be understood that for any desired degree of pressure supplied tothe chamber 49 and the diaphragm 55, the speed of the engine will becorrespondingly increased until a point is reached such that theopposing force exerted by the centrifugal weights is such as to overcomethe force exerted by uid pressure on the diaphragm with resultantmovement of the diaphragm and the valve operating element to the leftto` a point such that both the inlet and exhaust valves are maintainedin closed position until such a time as the pressure in chamber 49 ischanged or the speed of the engine changes to vary the opposing forceand cause movement of the valve operating element in one direction orthe other.

vThus the action of the centrifugalv governor mechanism will ten-d tocontrol the operation of the valves to maintain the pressure in theactuator I6 at a value such that the speed of the engine will always bedirectly proportional to the pressure supplied to the chamber 49, and inorder that the pressure may be properly controlled by the operator, thecontrol valve 36 is so constructed, as more particularly illustrated inFig. 2, as to supply a pressure to the chamber 49 which is substantiallyproportional to the degree of movement of the operators control element.The valve is provided with a casing 13 having an inlet chamber 14, anoutlet chamber 15, a diaphragm chamber 16 and an exhaust chamber 11, theinlet chamber being separated from the outlet chamber by means of aported partition 18, and the port in the partition being normally closedby means of an inlet valve 19 provided with a stem 80 having an exhaustvalve 8| provided at its upper end. A spring 82, interposed between theexhaust valve and the partition, normally maintains the inlet valve inclosed position as shown. A valve operating element 83 isslidably'mounted in a bore 89 formed in a partition 85 which serves toseparate the outlet chamber from the diaphragm chamber, the valve beingprovided with a centrally located bore 86 in communication at one endwith the exhaust chamber and with the outlet chamber at the other end,downward movement of the element serving to contact the exhaust valve toclose the lower end of the bore and to subsequently open the inlet valveto permit communication between the inlet chamber 14 and outlet chamber15. The valve operating element is normally maintained in the positionshown by means of a relatively light spring 81l interposed between theelement and the partition 85, and the diaphragm chamber is connectedwith the outlet chamber by means of a restricted passage 88. Thediaphragm chambers and exhaust chambers are separated by means of ailexible diaphragm 89 suitably carried by the housing as shown, thecentral portion of the diaphragm being clamped to the element 83 bymeans of a suitable nut 90. In order that the operation of the valvesmay be controlled by the operator, the upper portion of the housing isprovided with a pair of brackets 9| serving to position a pair ofbushings 92, these bushings extending inwardly from the brackets asshown and serving to engage the bore 93 of bosses 94 formed as a part ofa valve operating cam 95, these bushingsserving in connection with thebosses to position the cam for rotating movement relative to the casingas shown. The upper portion of the cam is provided with bosses 96 and anoperating lever 91 is pivotally mounted thereon for movement in theplane of the drawing by means of a suitable pivot pin 98. The cam isshaped more particularly as shown in Fig. 4 of the drawing, beingprovided with a cam surface 99 adapted to engage a plunger |00 slidablymounted in the upper part of the casing and operatively connected withthe nut 90 on the valve operating element 83 by means of a graduatingspring |0|, movement of the lever to rotate the cam thus serving todepress the plunger |00 and to transmit force to the valve operatingelement through the graduating spring and nut. Thus on movement of thelever in a counter-clockwise direction as viewed in Fig. 3, the valveoperating element will be moved downward to first contact the exhaustvalve and close the bore 86 and to subsequently open the inlet valve toadmit iiuid from the inlet chamber 14 to outlet chamber 15,

6: and since the outlet chamber is connectedwith the diaphragm chamber`by means of the restricted passage 88, it will be understood that theydiaphragm will be subjected on its lower side to the pressure in theoutlet chamber, thus causing an upward force on the valve operatingelement tending to oppose the force exerted by the graduating spring andto effect movement of both the valves to closed position when the upwardforce on the diaphragm slightly exceeds the force exerted by thegraduating spring, this action being wellknown in connection withcontrol valves of the self-lapping type as will be readily apparent'tothose skilled in the art. The pressure maintained in the outlet chamberwill therefore at all times be substantially proportional to the degreeof movement of the plunger |00, and substantially proportional to thedegree of movementof the control lever 91 in the event the cam isdesigned to have a lift which increases directly in accordance with theangle of movement thereof.

Fluid pressure is supplied to the above valve mechanism by means ofconduits 26 and 31, the conduit 26 being connected with the reservoirand the conduit 31 being connected to the inlet chamber 41. The valvemechanism is provided with outlet ports |02 and |03, the former beingconnected with the centrifugal control valve 3| through the medium ofvconduit 39, and the latter being connected with the centrifugal controlvalve 30 through the medium of conduit 38. Separate control valvemechanisms are interposed between the outlet chamber and the outletports |02 and |03, the valve shown at the right of the drawing having aninlet chamber |04 having a connection with the outlet chamber 15 throughports |05 and an outlet chamber |06 connected with the outlet port |02.The chambers |04 and |00 are separated by means of a ported partition|01, communication between the chambers through the ported partitionbeing controlled by means of an inlet valve |08 provided with anupwardly extending stem |09 having an exhaust valve ||0 attached at theupper end, the valve assembly above described being normally urged in anupward direction by means of aspring interposed between the partitionand the exhaust valve. This valve assembly is adapted for operation bymeans of a valve operating member ||2 slidably mounted in the casing asshown and being provided with a bore ||3 at its lower end, this borebeing open at the lower end and connected at its upper end with theexhaust chamber 11' by means of ports ||4. The valve operating member||2 is normally urged in an upward direction by means of a spring ||5interposed between the casing and a suitable washer ||6 slidably mountedon the member and held against upward movement by means of a pin 1.Operation oi the plunger is controlled by meansA of a sliding cam member||8 slidably mounted in the bushings 92 and being adapted for endwisemove.- ment on corresponding rocking movement of the lever 91 about thepivot pin 98, by virtue of its connection therewith through shoulders||9 and |20 formed thereon and adapted to engage a forked end portion|2| formed on the lower end of the operating lever. The right end of thecam member ||8 is provided with cam surfaces |22 and |23, the upper endof the plunger ||2 normally resting against the surface |22 and beingmaintained in that position by means of the spring H5. Thus with theparts in the position shown, the inlet and exhaust valves |08 and ||0serve to ,permit communication between the voutletA chamber 15 and theoutlet port |02 through ports |05, inlet chamber |04, partition |61 andoutlet chamber |06, and to prevent communication between the outlet port|02 and the exhaust chamber 11, while on movement of the lever 91 in aclockwise direction about the pivot pin 98, the cam member H8 will bemoved to the left, allowing the plunger ||2 to move upward as it engagesthe cam surface |23. When this action occurs, the plunger ||2 will bemoved upward under the action of spring to permit closing of the inletvalve and opening of the exhaust valve ||0 to prevent communicationbetween the chamber |04 and the outlet port |02 and to establishcommunication between the outlet port and the exhaust chamber 11, theexhaust chamber being provided with an atmospheric port |24, while onmovement of the lever 91' in a counterclockwise direction from theposition shown no change will occur in the position of the plunger ||2in view of the shape of the cam surface |22. In like manner, the leftside of the Valve mechanism is provided with a pair of similar intakeand exhaust valves |25 and |26 for controlling the connection between aninlet chamber |21 and an outlet chamber |28, as well as between theoutlet chamber |28 and the exhaust chamber 11, the valve being biased inan upward direction by means of a spring |29 interposed between theexhaust valve and a ported partition |30 which serves to separate thechambers |21 and |20, the chamber |21 in turn being connected with theoutlet chamber 15 by means of suitable ports |3|. The operation of thesevalves is controlled by a plunger |32 identical inconstruction with theplunger ||2 and provided at its lower end with a bore |33, open at itslower end and connected at its upper end with the exhaust chamber 11 bymeans of ports |34. This plunger is biased in an upward direction bymeans of a spring |35 interposed between the casing and a washer |36prevented against upward movement by means of va pin |31, the upper endof the plunger being in contact with a cam surface |38, identical inshape with the cam surface |22 and formed on vthe opposite end of themember H8. In like manner, a second surface |33 is formed on the leftend of the member H8, this surface being of the same shape as that ofthe surface |23 but oppositely disposed. Thus on counter-clockwiserotation of the lever 91 about the pin 98, the cam member ||8 will bemoved to the right and the upper end of the plunger will engage the camsurface |39 to permit upward movement of the plunger and consequentclosing of the inlet valve |25 and opening of the exhaust valve |26, itbeing apparent that during this action, the position of the plunger |2will remain unchanged from that shown in the drawing.

From the foregoing description, it will be readily understood that theconstruction of the control valve 36 is such that on normal operation ofthe control lever in a plane vertical to the plane of the drawing asshown in Fig. 2, fluid pressure will be supplied to the outlet ports |02and |03 in an amount proportional to the degree of movement of lever 91,and consequently to the left sides of the diaphragms in the centrifugalcontrol valves 30 and 3| through conduits 38 and 39, the same pressurethus being applied to the diaphragms of both centrifugal control valvesat all times during this type of operation of the mechanism. In manycases, however, it is necessary for the operator to control the speed ofone of the engines while maintaining the other engine or engines atidling speed, and this can be accomplished in the present instance byrocking the lever about the pivot pin 98, rocking of the lever in aclockwise direction as Viewed in Fig. 2 serving to prevent the supplyingof fluid pressure to the centrifugal Valve 3| to control the pressure inthe actuator |1, and movement of the lever in the reverse directionserving to give the reverse control operation. On the other hand,movement of the lever 91 to rotate the cam 95 serves at all times tooperate the valves 19 and 8| to supply fluid pressure to the outletchamber 15, in an amount proportional to the degree of movement oi thecam, and it will thus be seen that movement of the lever in the abovemanner will serve to lsupply uid pressure to the outlet chamber 15 whilemovement of the lever about the pivot pin 98 will serve to selectivelyprevent this fluid pressure from being supplied to one or the other ofthe centrifugal control valves and to thus control only the speed ofthat engine which is controlled by the centrifugal valve to which theuid pressure is supplied. Thus, by operating a single lever, theoperator may maintain both of the engines at any desired synchronizedspeed, or may individually control the speed of either engine, or thespeed of a group of engines in order to steer the airplane whenmaneuvering on the ground.

Assuming that both the engines are identical, it will be apparent thatsubstantially the same degree of throttle opening for both engines willbe necessary to maintain these engines at the same speed, but in theevent the efficiency of the engine 6, for example, is lessened for somereason, an increased opening of the throttle will be necessary in orderto maintain the speed at the same value as that of engine 1. Such a dropin eciency will immediately be reflected in the speed of the centrifugalgovernor which controls the pressure in the actuator l5, and thisdecrease in speed will permit the fluid pressure acting on the diaphragm55 to open the intake valve of the control valve 30 to correspondinglyincrease the pressure supplied to the actuator I6, a new condition ofbalance being reached eventually wherein the pressure in the actuator I6is greater than the pressure in the actuator I1, with a correspondinglygreater throttle opening for the engine 6, thus synchronizing the speedsof the engines with different degrees of throttle opening for the twoengines. It is desirable that the operator be advised of any suchdecrease in eiciency of one of the engines, and this is accomplished inthe present instance by means of the pressure gauges 40 and 4| whichserve to indicate to the operator the pressures in the actuators I6 and|1, it being obvious that in the event the pressure gauge 40 shows ahigher reading than the pressure gauge 4|, the efficiency of engine 6 isless than that of the engine Thus a reliable indication of the relativeeicienoies of the engines is available to the operator at all times.While the above system has been shown as applied to a pair of engines,it will be clearly understood that a group of engines may be controlledin substantially the same manner, if desired.

Although the invention has been illustrated and described withconsiderable particularity, it is to be understood that the same is notlimited to the form shown but may receive a variety of mechanicalexpressions as will readily appear to those skilled in the art.Reference will, therefore, be had to the appended claims for a denitionyof the limits of the invention.

What is claimed is:

1. The combination with a plurality of engines each having a controlelement for controlling the speed of the engine, of uid pressureoperated means for controlling the operation of the said elements andsynchronizing the speeds of the engines including a uid pressureactuator for each element, individual means responsive to the speed ofeach engine for controlling the fluid pressure energization of eachcorresponding actuator, each of said means including a self-lappingvalve device having a pressure responsive member associated therewith,and including also a plurality of governor weights driven by therespective engine and arranged to move the pressure responsive member inaccordance with changes in engine speed, and means for subjecting all ofsaid pressure responsive members to the same degree of uid pressure tocontrol said speed responsive means comprising a self-lapping valvedevice having a supply valve, a plurality of release valves and adiaphragm ccnstructed and arranged to maintain said same degree ofpressureirrespective of variations in the position of said pressureresponsive member caused by operation of said governor weights.

2. The combination with a plurality of engines each having a throttlecontrol element for controlling the speed of the engine, of air pressurecontrol means for controlling the operation oi said elements andsynchronizing the speeds of the engines including a pressure operatedactuator for each element, individual means responsive to the speed ofeach engine for controlling the supply of air pressure to eachcorresponding actuator, each of said means including a selflapping valvedevice having a diaphragm associated therewith, and including also aplurality of governor weights driven by the respective engine andarranged to move the diaphragm in accordance with changes in enginespeed, and means for subjecting said diaphragms to the same degree ofair pressure to control said speed responsive means comprising aself-lapping valve device constructed and arranged to maintain said samedegree of pressure irrespective of variations in the position of saiddiaphragm caused by operation of said governor weights.

3. The combination with a pair of engines, each having a control elementfor controlling the speed thereof, of fluid pressure control means forcontrolling the operation of said elements including a iiuid actuatorfor each element, separate self-lapping valve means for controlling thesupply of fluid pressure to each actuator, means for controlling theoperation of each of said valve means including a centrifugal governorresponsive to the speed of the corresponding engine and a iluid motor, acontrol member mounted for movement in two diierent intersecting planes,a self-lapping control valve having a connection with each of saidmotors and operable on movement of said control member in one plane tosupply iluid pressure to said motor at a pressure proportional to thedegree of movement of said member, and means operable on movement ofsaid control member in either direction in the other plane for closingthe connection to either of said motors so that the pressure applied tothe other motor is substantially proportional to the degree of movementof said member in said one plane, said control valve including adiaphragm and a supply valve constructed and arranged to maintainconstant the pressure supplied thereby regardless of the action of saidgovernor.

WILFRED A. EATON.

REFERENCES CITED The following references are of record in the i'lle ofthis patent:

UNITED STATES PATENTS Number Name Date 1,538,167 Chappell May 19, 19252,081,946 Martin June 1, 1937 2,082,410 McCauley June 1, 1937 2,103,274Sanford Dec. 28, 1937 2,138,148 Eckert Nov. 29, 1938 2,148,305 SanfordFeb. 21, 1939 2,251,293 Schwartz Aug. 5, 1941 2,265,260 Argo Dec. 9,1941 2,322,518 Huber June 22, 1943

